Container holding devices for holding containers, which store powder, liquid, gas and the like, are used in various fields. For example, a container holding device is used in image forming apparatuses for holding a toner container. In case of the image forming apparatuses, a holding part holds the toner container, and a toner conveying device supplies the toner to a developing device of the image forming apparatus.
Toner containers made of hard materials, such as bottles or cartridges, are known. However, the hard toner containers do not shrink when the toner is finished.
Japanese Patent Application Laid-Open Publication Nos. 2001-194907, 2001-324863, and 2002-72649 disclose toner containers that are bag-shaped, made of soft material, and can be reduced in size and volume by a suction pump. These soft toner containers shrink when the toner is finished. The soft containers are better than the hard containers in various respects. For example, because the soft containers shrink, more containers can be accommodated in the same space, so that the transportation costs of returning used toner containers to the manufacturer can be reduced.
However, when the soft toner container shrinks, creases are formed on the container and the toner gets caught in the creases, and cannot be stably supplied to the toner outlet. One approach is to provide fold lines on the container, so that the container shrinks in a fixed shape along the fold lines, and is neatly folded without creases. However, creases are formed even if fold lines are provided. A countermeasure is to provide pressurizing guide members (external pressurizing means) that apply pressure along the fold lines.
However, the pressurizing guide members become obstacles when replacing an empty toner container with a new container. Therefore, the user is required to strongly push the new toner container into its position, against the force of the pressurizing guide members. However, creases are formed on the toner container when it is strongly pushed into its position. In addition, if such creases are created, the container does not fold into a fixed shape along the fold lines, when shrinking. Also, the toner container is apt to tear when being fixed, because of the pressurizing guide members. Therefore, a relatively rigid material has to be used on the container where the fold lines are provided, however, the rigid material is hard to shrink.
These problems are not limited to the container holding device used for the toner conveying device in the image forming apparatus. Such problems also apply to any other container holding device for holding a soft container that shrinks as the contents are ejected.